Abstract : The ABM '95 experiment was conducted in May and June of 1995 on the Camp Pendleton Marine Base in Southern California. Several institutions participating in the experiment deployed various types of sensor systems. Data collected by two bottom hydrophone arrays, the moored sonobuoys, and the land-based air acoustic array are presented. An extensive set of environmental and ancillary data were also collected to support these measurements. Observations of the properties of the background sound field from 1 Hz to 10 kHz are presented. Signals generated by shs, amphibious craft, and aircraft, although prevalent in the data, are excluded from the discussion.